Luis has walked his dog for a total of $40$ kilometers since he started walking daily. He has been walking $8$ kilometers each day. For how many days has Luis been walking?
Answer: The number of days that Luis has been walking is the total number of kilometers walked divided by the number of kilometers walked each day. $40\text{ kilometers} \div 8\text{ kilometers per day} = \text{number of days walking}$ $40\text{ kilometers} \div 8\text{ kilometers per day} = 5\text{ days}$